I'm just putting it out there for everyone who insists that DW beats the crap out of 2H for DPS. That is not always the case and the real answer is that it depends on the situation. 1 on 1 with a tough enemy (such as a dragon or a boss), yes, fair enough, but in a room packed full of weaker enemies? Not a chance.
Even when facing just 2 enemies, a 2H using sweep effectively doubles its DPS, and this multiplier increases linearly depending on the number of enemies within striking distance in an 180 degree arc infront of you. Due to the enhanced range of a 2hander, the sweep will cover a huge area so you don't even need to worry about precise positioning.
Another comment I've been seeing is that 2handers are rubbish at blocking. Well this isn't true for me. I have invested in all the perks up the right hand side of the blocking tree, and while blocking with my 2H greatword, I can tank giants for minutes at a time without healing. If I stop blocking then I probably won't last more than about 5 hits. It does make a huge difference to physical damage reduction, even without a sheild. Plus I can still power bash and disarm just like a shield user.
I'm not saying that 2H is the ultimate weapon, but I do not believe that the DPS race is as clear cut as some make it out to be.
Two-handed DPS relies solely on the use of a very exposed and slow side power attack. Furthermore, it's reach isn't as great as you make it out to be. Most encounters I've seen don't have enemies who are all aligned with each other. Often times you will find enemies that are separated and even shooting you from different directions. Speaking about slow attacks, I find that EVERY two-handed weapon attack makes you a far easier target to arrows and magic than any other weapon attack.
In any case, I find that dual-wielding provides more consistent damage and more consistent DPS. You also get the versatility of doing less overkill damage far more quickly than a two-handed weapon can deliver. In addition, your power attacks do far more damage to blocking opponents because you deliver three strikes, three strikes of which the first strike breaks the block and then the two following strikes land block free delivering massive damage.
Honestly, what I've found with two-handed weaponry (Which I used for a great deal of my play-through) is that it's slow. It's very slow. Not only that, it limits your movement far more than one-handed weapons do, making your reach a non-factor in most cases. This is especially true in cramped dungeons. The slowed movement when striking also makes your footwork very inferior to someone using a one-handed weapon.
As for blocking, while I haven't tested it much for two-handed weapons, I've found that to reach the blocking cap, I need to have at least a shield, 5 rank +block perks, and a 40% fortify block enchantment. I imagine the requirement is probably a bit steeper for two-handed weaponry and it might not be capable of reaching the same blocking cap (Educated guessing based on the previous games). In any case, without a shield you lose out on the Deflect Arrows perk, Elemental Protection perk, a shield's armor rating (Which may or may not be a factor), a shield's enchantment, and most importantly, a shield's bash.
A shield's bash is far superior to that of a two-handed weapon. It fires off slightly quicker. It also has more range. Furthermore, it produces a much more staggering effect (Meaning enemies stagger for longer). This effect is further enhanced if you meditate on Fus. With a shield you also have access to shield charge which has the ability to trivialize nearly all melee combat (It's basically a melee Fus-Ro-Dah that you can do whenever you want as long as you can sprint).
Personally, I would find two-handed weaponry to be much more desirable if it didn't cripple your movement while swinging. If the swings were actually faster. The only thing a two-handed weapon has going for it is the sweep perk. That's the only thing it has going for it. It has far too many negatives for way too little positives.
Personally, after extensive testing, I feel that the race is clear cut. Sweeping is way too situational and waiting for enemies to align as you previously stated isn't my idea of fun. For me it's either finesse, versatility, and defense (Sword and board) or raw DPS with dual-wielding. It's really no contest. This is especially true when you consider that most enemies are capable of blocking. That a dual-wielding's perked power attack deals an insane amount of damage. That this particular power attack breaks through the block while still continuing on and getting hits in which are not blocked. You also have to consider dual-wielding's speed perks and that it has the most powerful power attack while perked.
Role playing wise, I like the concept of two-handed weaponry. Heck, I even tried it for a large portion of the game. However, it just didn't cut the mustard. Too many cons and not enough pros. I also don't find it as fun because footwork is severely crippled when using two-handed weaponry as opposed to one-handed weaponry. I find sword and board + block runner + quick reflexes to be the most fun. Just my two cents.